PHP handled CSV not generating in linux environment - php

Question

hi im currently using a script which generates csv and sends its download link(destination) in a email. in the following code,the email is sent correctly but it does not generate the csv.
Code
$fileD = "Weekly_Report_From_".date('d-m-Y', strtotime('-1 week'))."_to_".date('d-m-Y').".csv";
$url_down = (Config_Reader::readProjectConfig('report')->exportDirectory.'/weeklyReport/'.$fileD);
echo "<br/>";
echo $url_down;
if(file_exists($url_down) == false){
echo "FILE DOES NOT EXISTs";
$fp = fopen($url_down, 'w');
$header = array("XX","XX","XX","XX","XX","XX","XX","XX","XX","XX");
fputcsv($fp, $header, ',');
foreach ($tables as $fields) {
fputcsv($fp, $fields,',');
}
}
else{ echo "FILE EXISTs";
$time_start = time();
$fileD = "Weekly_Report_From_".date('d-m-Y', strtotime('-1 week'))."_to_".date('d-m-Y')."#".$time_start.".csv";
$url_down = (Config_Reader::readProjectConfig('report')->exportDirectory.'/weeklyReport/'.$fileD);
$fp = fopen($url_down, 'w');
$header = array("XX","XX","XX","XX","XX","XX","XX","XX","XX","XX");
fputcsv($fp, $header, ',');
foreach ($tables as $fields) {
fputcsv($fp, $fields,',');
}
}
header("Pragma: public");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: private",false);
header("Content-Transfer-Encoding: binary");
fclose($fp);
$mail = new Zend_Mail ();
$sentFromEmail = $config->sentFrom_new;
$tr = new Zend_Mail_Transport_Sendmail ( '-f' . $sentFromEmail );
Zend_Mail::setDefaultTransport ( $tr );
$mail->setReturnPath($sentFromEmail);
$mail->setFrom ( $sentFromEmail, 'Reporters' );
$rty = "Hi,<br /><br />This system is working perfectly Report.";
$mail->setBodyHtml ( $rty );
$mail->addTo ( $weeklyReportRecipients );
$mail->setSubject ( "Weekly Report" );
try {
$mail->send ();
echo "success";
}
when i go in more detail. it always prints the file does not exist which is correct but it never makes the csv inside the directory,
I allowed all read write and excute permissions to the weeklyReport folder as well, but still no luck,, will any body be able to help me over this...
P.S $tables is the array that take use of to generate the csv... that works fine. and also $weeklyReportRecipients, $sentFromEmail are obtained from the config file and they are also working fine